This invention relates to solid propellant rocket motors and, more particularly, to a barrier system to be placed between the two pulse grains of a dual pulse solid propellant rocket motor.
In a solid propellant rocket motor, the propellant material is contained within a combustion chamber which confines the reaction products of combustion. The physical body or mass of the propellant material is referred to as the grain and, in some motors, there is more than one grain inside the combustion chamber. This arrangement is called a dual pulse motor and its operation presents an ignition problem. If the separate grains within the same combustion chamber are not properaly separated, then the ignition of one pulse grain often initiates the premature combustion of the second pulse grain.
As a consequence of the above, a considerable research effort has evolved with the purpose of providing a proper barrier which will prevent second pulse ignition during first pulse burning. Another problem is involved in the igniting of the second pulse grain since it must take place at a predetermined time after the first pulse grain burnout. Concurrent with the above problems is the fact that the structural and thermal integrity of the dual pulse motor must be maintained during its operational phase.
Previous attempts at solving the above problems have not proved too successful. However, with the present invention, a barrier system has been found that can effectively prevent the ignition problems of dual pulse motors. The barrier system is composed of two double layers of rubber forming a restrictor assembly in which one double layer forms a grain restrictor for pulse grain No. 1 and the second double layer forms a thermal barrier for pulse grain No. 2. The restrictor assembly is positioned between the first and second pulse grains to form an ignition barrier and in turn is adhesively attached to the rocket case liner by means of a rubber impregnated glass cloth.
Accordingly, the primary object of this invention is to provide a barrier system for overcoming the ignition problems encountered during the operation of dual pulse rocket motors.
Another object of this invention is to provide a barrier system to be placed between the first and second pulse grains of a solid propellant dual pulse rocket motor.
Still another object of this invention is to provide a barrier system for dual pulse rocket motors that is capable of preventing second pulse grain ignition during first pulse grain burning.
A further object of this invention is to provide a barrier system for dual pulse rocket motors that allows for the ignition of the second pulse grain at an appointed time after first pulse grain burnout.
Still a further object of this invention is to provide a barrier system that maintains structural and thermal integrity of the total motor during its operational phase while simultaneously overcoming the ignition problems often encountered with dual pulse rocket motors.
The above and still further objects and advantages of the present invention will become more readily apparent upon consideration of the following detailed description thereof when taken in conjunction with the accompanying drawing.